Variations of physico-mechanical, mineralogical and geochemical properties of marble under the influence of weathering

Purpose. To investigate the physico-mechanical, mineralogical and geochemical properties variations of Igbeti marble, south-western Nigeria under the influence of weathering. Methods. About twenty representative samples were collected at a varying depth up to a depth of 30 meters from the study area. The samples represented a group of unweathered, slightly weathered, moderately weathered and highly weathered rocks using weathering classification indices. Thin sections were prepared for textural and mineralogical studies of the rock samples. The chemical composition analyses of the rock samples were conducted using X-ray Fluorescence spectrometry (XRF). The physico-mechanical properties were also evaluated. Findings. The results showed that noticeable mineralogical and chemical changes occur in the rock fabric because of the increase in weathering state. The laboratory tests result also revealed that weathering reduces the strength of the rock. Originality. The transformation of physical and mechanical properties of rocks because of weathering is a major concern to the geotechnical engineers. These properties have been investigated by the researchers, but the majority of the available researches were conducted on weathered sedimentary and igneous rocks while that of metamorphic rock is very scarce. Hence, this study investigates the influence of weathering on physico-mechanical, mineralogical and geochemical properties of Igbeti marble, south-western Nigeria. Practical implications. The obtained results show that the transition of selected rock properties as a result of weathering would significantly affect slope stability and performance of the rock in engineering applications.Мета. Вивчення змін фізико-механічних, мінералогічних і геохімічних властивостей мармуру родовища Ігбеті (південно-Західна Нігерія) під впливом вивітрювання. Методика. Було відібрано 20 репрезентативних зразків на різних глибинах залягання породи (максимум – 30 м) у районі родовища. У відповідності з класифікаційними індексами вивітрювання зразки були розділені на групи: невивітрені, слабо вивітрені, помірно вивітрені, сильно вивітрені. Було виготовлено тонкі стрічки для вивчення текстурних і мінералогічних характеристик. Аналіз хімічного складу зразків проводився із використанням рентгенофлуоресцентної спектрометрії (РФС). Також була проведена оцінка фізико-механічних властивостей зразків. Результати. Результати досліджень показали, що значні мінеральні та хімічні зміни у товщі породи пов’язані з наростанням впливу вивітрювання. Встановлено за даними лабораторних досліджень, що об’ємна щільність, суха щільність, суха та питома вага, збільшуються з підвищенням ступеня вивітрювання, проте зміст води/вологи, водопоглинання, пористість, міцність на одноосьове стиснення, міцність при точковому навантаженні, міцність на розтяг та твердість за Шмідтом зменшуються. Встановлено зв’язок кількості домінуючих компонентів (кальцит і доломит) та інших силікатних і несилікатних мінералів зі ступенем вивітрювання. Наукова новизна. Для умов родовища Ігбеті виявлено характер та особливості впливу ступеня вивітрювання на зміну фізико-механічних і геохімічних властивостей мармурових порід метаморфічного типу, у той час як попередні дослідження присвячені осадовим та магматичним породам. Практична значимість. Результати досліджень необхідно враховувати в архітектурному та інженерному використанні у різних кліматичних зонах. Поняття впливу вивітрювання на властивості гірських порід є важливим критерієм для визначення глибини розробки, конструкції похилого схилу, методу, простоти видобутку та напрямів використання мармуру, що дозволить зменшити вартість і поліпшити роботи з розвідки й видобування.Цель. Изучение изменения физико-механических, минералогических и геохимических свойств мрамора месторождения Игбети (Юго-Западная Нигерия) под влиянием выветривания. Методика. Было отобрано 20 репрезентативных образцов на различных глубинах залегания породы (максимум – 30 м) в районе месторождения. В соответствии с классификационными индексами выветривания образцы были разделены на группы: невыветренные, слабо выветренные, умеренно выветренные, сильно выветренные. Были изготовлены тонкие срезы для изучения текстурных и минералогических характеристик образцов. Анализ химического состава образцов проводился с использованием рентгенофлуоресцентной спектрометрии (РФС). Была также проведена оценка физико-механических свойств образцов. Результаты. Результаты исследований показали, что значительные минералогические и химические изменения в толще породы связаны с нарастающим влиянием выветривания. Установлено по данным лабораторных исследований, что объемная плотность, сухая плотность, сухой вес и удельный вес увеличиваются с увеличением степени выветривания, а содержание воды/влаги, водопоглощение, пористость, прочность на одноосное сжатие, прочность при точечной нагрузке, прочность на растяжение и твердость по Шмидту уменьшаются. Установлена связь количества доминирующих компонентов (кальцит и доломит) и других силикатных и несиликатных минералов со степенью выветривания. Научная новизна. Для условий месторождения Игбети выявлен характер и особенности влияния степени выветривания на изменение физико-механических и геохимических свойств мраморных пород метаморфического типа, в то время как предыдущие исследования посвящены осадочным и магматическим типам пород. Практическая значимость. Результаты исследований необходимо учитывать в архитектурном и инженерном использовании в разных климатических зонах. Понимание влияния выветривания на свойства горных пород является важным критерием для определения глубины разработки, конструкции наклонного склона, метода, простоты добычи и направлений использования мрамора, что в итоге позволит снизить стоимость и облегчить работу по разведке и выемке.The authors appreciate the custodians of rock mechanics laboratory at the Federal University of Technology Akure, Nigeria, geology laboratory at the University of Ibadan, Oyo State, Nigeria and Centre for Energy Research and Development at Obafemi Awolowo University Ile-Ife, Osun State, Nigeria for making the laboratories available for the experiments

Detection and distribution of seed-borne viruses on commercial cowpea (Vigna unguiculata (L.) Walp) cultivars in Ado-odo Ota, Ogun Sate, Nigeria

Cowpea is a major source of dietary protein in the nutrition of people in sub-Saharan Africa. Many viruses have been reported to cause economic reduction in cowpea productivity in Nigeria. However, their current distribution is not well documented while most farmers source their seeds from local markets. This study investigated the detection and distribution of seed-transmitted viruses on commercial cowpea cultivars in Ado-odo Ota Local Government area (LGA) of Ogun State. Cowpea seed samples were collected from eleven markets in the LGA. Coordinates of the locations were recorded with Geographical Positioning System (GPS). Thirty cowpea seeds from each market were sowed in planting pots under screenhouse conditions and seedlings were observed weekly for visible virus symptoms. Four-week old seedlings were tested for viruses using Antigen Coated Plate-Enzyme-Linked Immunosorbent Assay (ACP-ELISA) and Reverse Transcription Polymerase Chain Reaction (RT-PCR). Samples were tested for seven seed-transmitted viruses namely Blackeye cowpea mosaic virus (BlCMV), Cowpea aphidborne mosaic virus (CABMV), Cucumber mosaic virus (CMV), Southern bean mosaic virus (SBMV), Cowpea mottle virus (CMeV), Cowpea yellow mosaic virus (CYMV) and Cowpea mild mottle virus (CPMMV). Seed germination rates ranged from 63.3±15.3% of seeds from Joju to 96.7 ±5.8% for Atan and Iju markets. All samples tested negative to ELISA and were confirmed negative by RT-PCR. These findings suggest absence of seedtransmitted cowpea viruses in the study area as at the time of sampling. Periodic detection survey is recommended to assure the virus-free status of the area.Keywords: ACP-ELISA, Cowpea viruses, Diagnostics, RT-PCR, Seed transmissio

Concurrent Engineering Implementation in Design-Build Railway Projects

Design-build as a procurement method is increasingly being used in the design and construction of greenfield rail networks, and that is despite the complexities that characterise rail networks—rail infrastructure projects involves significantly more complex systems such as safety, telecommunications, signalling and electrification. One of the key drivers for this choice of procurement method for the delivery of rail networks is that the design-build contractor commits to an aggressive schedule and implements strategies to enable the works to be completed to time and cost. One of such strategies is the application of concurrent engineering principles to the design and construction works. This Chapter gives an overview of concurrent engineering as applicable to design-build rail projects, focusing mainly on the design as an activity. It identifies factors that impact the application of concurrent engineering as well as mitigations that can be applied for the successful application of concurrent engineering principles in design-build rail projects

Variable Thermal Conductivity and Viscosity Flow past a Stretching Porous Surface with Viscous Dissipation through a Porous Medium

In this work, we study variable thermal conductivity and viscosity flow past a porous surface with viscous dissipation through a porous medium. We transformed the governing partial differential equations into ordinary differential equations in terms of a suitable similarity variable.  We employed Galerkin weighted residual method to solve the resulting non-linear equations. The results show the effects of variable viscosity parameter, variable thermal conductivity parameters and those of viscous dissipation parameter on the flow system

Do Financial Risks affect Financial Performance of Listed Insurance Firms in Nigeria?

The study assessed the effect of financial risks on the financial performance of listed insurance firms in Nigeria. The population of this study consists of all listed insurance firms in Nigeria. However, ten (10) insurance firms were selected as sample. The selection of these insurance firms was done using judgmental sampling technique. Data for the study were extracted from their annual reports covering 10 years, from 2015 to 2021. Panel data method was employed for analysis using E-view 10.0. Results revealed that only liquidity risk (LDR) has negative and significant effect on financial performance, while the effect of credit risk and leverage risk is insignificant among the sampled insurance firms. It is concluded that liquidity risk tends to significantly impair the financial performance, if not properly monitored and mitigated. Following this, the study recommends that the sampled insurance firms should continually develop and implement risk management policies and strategies that will help reduce their risk profile in order to improve their financial performance

Reacting Laminar flow with Applied Magnetic Field in a Channel filled with Saturated Porous Media

In this work, we examined reacting laminar  flow of a third grade fluid in a channel filled with saturated porous media under the effect of applied  magnetic field and variable thermal conductivity. It is assumed that the fluid has temperature-dependent viscosity and reacts satisfying Arrhenius law. We employed Galerkin weighted residual method to solve the resulting non-linear equations. The results show the effects of variable viscosity parameter, Brinkman number, Reynolds number, Prandtl number, Darcy number, Hartmann number and parameter on the flow system

Use of Social Media for Marketing of Agricultural Commodities in Selected Markets in Ibadan metropolis, Oyo State, Nigeria

This study examined the use of social media for marketing agricultural commodities in Nigeria particularly in Ibadan metropolis. Descriptive survey design was used to carry out the study, while 100 questionnaires were used to obtain data from the market traders of Agricultural products in Ibadan. Data was analyzed using descriptive (mean, frequency, standard deviation, percentages) statistics. The result shows that majority of the respondents were female (61%), married (36%) and within the age range of 30-35 years. The findings also revealed that Instagram, Facebook and Youtube are the most used social media App among the respondents and almost all the respondents (96%) spend more than 1 hour daily on social media for advertising their products. The study further revealed that Facebook and Instagram were the most preferred social media tools for product marketing by the respondents. The study therefore shows that social media was used to a very high extent to enhance customer relationship and increase sales due to its mode of operation in marketing agricultural commodities. It’s recommended that agricultural commodities sellers should learn more on how to effectively use social media for agricultural commodity marketing

Nigerian University Libraries and the Challenges of Globalization: The Way Forward

Abstract The main aim of this paper is to examine the importance, implications, and opportunities opened to Nigerian libraries in the current Information Age as related to the concept of globalization. This paper shall attempt to address possible areas of importance and advantages that can propel Nigerian universities and their libraries into being a respective player in the global IT revolution and enhance their status in what is now widely called as Global Village. This paper stresses the necessity for Nigerian universities to be part of the new and emerging technologies which are challenging the traditional process of teaching and learning and the way education is managed. Strategies of leap-frogging Nigerian libraries into an enviable position of Information Technology will be carefully articulated in this paper

Determinants of Youth’s Participation in Agricultural Enterprises in Rural Communities of Ogun State, Nigeria

Agriculture is a source of livelihoods for most rural people, but majority of the rural populace face many hurdles such as lack of access to credit and other resources necessary to earn a livelihood. However, despite the opportunities available in agriculture, unemployment rate and rural-urban migration is still high and on the increase. This study was designed to identify the determinants of youth participation in agricultural enterprises in Ogun State, Nigeria. Multi-stage sampling technique was used to select 125 farmers (youths) for the study. A well-structured questionnaire was used in collecting the data and data were analyzed using descriptive statistics. The results show that many (30.4%) were between 30-34 years of age, majority (59.2%) of the respondent recorded household size 1-3 persons. Majority (52.0%) of the respondents are into farming as their primary occupation, 83.2% strongly agree that agricultural enterprise reduced dependency on government and the community, 83.2% noted subsidy on fertilizer is not available, 96.8% indicated highly benefited on increase in self-worth, 79.2% encountered poor returns to investment as the severe constraint, 96.0% were fully involved in cassava production, while 95.2% participated in maize production. These youths are confronted with different challenges constraining their participation in agricultural enterprises. Hence, access to credit facilities, increase in farm size will enable youths to participate in the available enterprises, thereby, increasing youth participation in agricultural enterprises and assist them to attain the efficient point on the production frontier